January 5 Heavy Snow and Subsequent Cold Spell

A powerful storm system brought heavy snow and near blizzard conditions to much of central Indiana on January 5, with a mix of rain and snow across southeast sections of the area. After the snow diminished during the evening, arctic air plunged into the area on strong winds. Temperatures plummeted and significant blowing and drifting of snow occurred. Temperatures remained below zero for over 24 hours at many locations, with wind chills around 40 below zero at times. Temperatures reached levels that had not been seen in 20 years. The snow and cold created dangerous travel conditions across much of Indiana and surrounding areas. Sections of interstates were closed down, and travel was restricted to emergency personnel only. Schools were closed for a week across parts of central Indiana.

What caused this event?

Water vapor satellite image shows large view
of system that brought the cold air. White lines
show 500mb heights. Yellow arrow shows basic flow
around the system. Click to enlarge.

The jet stream dove south into the southern United States, allowing cold air straight from the Arctic to flow south into the USA. (For information on the "polar vortex", please visit this climate.gov article). This cold air interacted with plentiful moisture being drawn northward with an area of low pressure at the surface. The result was heavy snow for several hours across the northwest half of central Indiana. Across the southeast part of the area, warmer air moved north and allowed for a period of rain. This cut down on snow amounts. As strong high pressure moved in behind the low pressure, winds increased across the area. Gusts of 30 to 40 mph were common Sunday night, resulting in blowing and drifting of the snow that fell. Gusty winds continued into January 6, creating dangerous wind chills.

Snowfall

Snowfall of 8 to 14 inches was common across areas generally along and north of a Terre Haute to New Castle line. Amounts dropped quickly to the south and east of this line due to warmer air allowing rain to fall for several hours. Areas that received heavy snow saw snow falling at a rate of an inch or more per hour during the height of the storm. At Indianapolis, snow fell at the rate of at least an inch per hour during the 10:00 AM to 3:00 PM time frame on January 5. Snowfall diminished by late afternoon but lighter snows continued into the evening. At Indianapolis, the 11.4 inches of snow that fell on January 5 was the second highest calendar day snowfall since records began, and that amount was a new record snowfall for the January 5 date. The Indianapolis record for most snowfall in a calendar day is 12.1 inches on March 19, 1906. At Indianapolis, only two other days in January have ever had greater than 10 inches of snow accumulate in 1 day: January 15, 1965 and January 26, 1978 (during the blizzard of '78).

Gusty winds ushering in the colder air brought blowing and drifting snow. Visibility was reduced in blowing snow across many areas through the day of January 6. This resulted in drifts of several feet at some locations. The snow and lowered visibility caused some roads to be shut down across parts of Indiana. Interstate 65 was shut down north of Lafayette. Some state highways and US highways were also closed. Many counties in Indiana declared travel warnings, meaning that only emergency vehicles were allowed on the roads.

A list of snowfall reports from central Indiana is at the end of this page. Below are some images related to the snowfall. Click any image to enlarge.

7 day plot of temperature and dewpoint at Indianapolis ending early January 10.

As arctic air flowed into the area, temperatures fell quickly during the evening of January 5 and into January 6. Readings bottomed out colder than 10 below zero across most of the area that saw significant snow. These temperatures often were the coldest seen since January 1994. Temperatures remained below zero for well over 24 hours at many locales. With gusty winds continuing through January 6, wind chills fell into the 30 to 45 below zero range for prolonged periods of time. The following table summarizes some temperature facts for sites across central Indiana, based on hourly observations at the site. Temperature and wind information was missing at Lafayette for several hours during the event.